CRISPR/Cas9-mediated genome editing: from basic research to gene therapy

CRISPR/Cas9 mediated genome editing is one of the most significant molecular tools discovered to edit the desired genes. It has ushered in a new era of novel possibilities of gene therapy. CRISPR/Cas9 system was originally observed as a part of the adaptive immune system in bacteria. It later on was adapted to carry precise and targeted alterations to the DNA in human cells to be used for gene therapy to correct genetic disorders and treat various severe diseases associated with the genetic changes. Besides this, the CRISPR/Cas9 system has been employed in pharmacogenomics to develop new drugs based on the patient’s genes, in modifying the organisms for research and even for diagnostic purposes in developing CRISPR based COVID-9 test. The recent approval of a CRISPR/Cas9 cellular gene therapy by FDA named “Casgevy” to treat sickle cell anemia is a testimonial to the potentials of CRISPR/Cas9 system in developing innovative gene therapies. This review details the mechanisms of CRISPR/Cas9 gene editing and its utilization in the ongoing clinical trials in the treatment of not only the monogenic disorders like sickle cell disease, thalassemia, and genetic blindness but also in treating multi-factorial diseases like cancers, cardiac diseases, diabetes, autoimmune diseases, viral infections such as human immunodeficiency virus (HIV) etc. An attempt has also been made to discuss the various limitations, challenges and ethical frameworks encompassing CRISPR/Cas9 based gene therapy in clinical settings.

Construction of human interleukin-26 lentivirus expression plasmid and gene knockout plasmid and their activity verification in HEK293T cells / 中国生物制品学杂志

@#Objective To construct a lentivirus-based expression plasmid and gene knockout plasmid of human interleukin(IL)-26 so as to lay a foundation of studying the function of IL-26 gene in cell signaling pathway and autophagy.Methods IL-26 gene sequence was amplified from human peripheral blood mononuclear cells by RT-PCR and cloned into pCDH-CMVMCS-EF1-copGFP eukaryotic expression vector to construct overexpression plasmid;Four knockout targets,Exon1sgRNA1,Exon1sgRNA2,Exon3sgRNA1 and Exon3sgRNA2,were designed based on the exon sequence of IL-26,and constructed into lentiCRISPRv2 vector by CRISPR/Cas9 technology to construct gene knockout plasmid. The overexpression plasmid and gene knockout plasmid were transiently transfected into HEK293T cells respectively,and the expression of IL-26 was verified by RT-qPCR and Western blot. In addition,amino acid sequence analysis,structure prediction and subcellular localization observation of IL-26 were performed.Results The results of restriction digestion,sequencing and bioinformatics analysis showed that IL-26 was 516 bp in length,encoding 171 amino acids. The IL-26 mRNA level and protein level of HEK293T cells transfected with IL-26 overexpression plasmid increased by 656. 789 times and 1. 978 times respectively with significant differences as compared with the normal control group(t = 17. 976 and 7. 859,P < 0. 000 1 and < 0. 001,respectively). With the transfection of 4 knockout targets Exon1sgRNA1,Exon1sgRNA2,Exon3sgRNA1 and Exon3sg-RNA2 into HEK293T cells,the expression of IL-26 decreased by 0. 930,0. 980,0. 523 3 and 0. 316 9 times,respectively,among which Exon3sgRNA2 significantly down-regulated the expression of IL-26(t = 7. 440,P < 0. 001). IL-26protein showed signal peptide structure and certain transmembrane function in the first 22 amino acids,which existed in cytoplasm.Conclusion IL-26overexpression and gene knockout plasmids were successfully constructed,which laid a foundation of the follow-up study of the function of IL-26.

Analysis of recognition sites and application for commercial and homemade antibodies to aquaporin 9 / 解剖学报

Objective To analyze the antigen recognition sites of commercial and homemade antibodies against aquaporin(AQP)9,and to identify the application effect.Methods Western blotting was used to compare the efficacy of three commercial antibodies and self-made antibody in identifying AQP9 genotypes.The antigen recognition sites of four antibodies and their specificities in practical applications were analyzed.Results Western blotting showed that protein bands of three commercial antibodies were detected in both WT and Aqp9-/-mice.The keyhole limpet hemocyanin(KLH)conjugated synthetic peptides corresponding to the three commercial antibodies were derived from rat,human and human,respectively.And The sequences of these three synthetic peptides were different from those of mice.AQP3/7 and AQP9 have similar molecular weight and were expressed in the liver with high homology.An obvious band of self-made antibody was observed at the 27 kD position in WT mice,but no band was observed at the corresponding position in Aqp9-/-mice.Conclusion Commercial antibodies 1 and 3 can be used to assist in the identification of genotypes in Aqp9-/-mice.Homemade antibodies can accurately identify genotypes at the protein level.

Construction of the pore-forming toxin gene exlA knock-out mutant of Pseudomonas aeruginosa and its basic characteristics / 军事医学

Objective To construct a non-trace deletion mutant of exlA in Pseudomonas aeruginosa strain NY8755(NY8755ΔexlA)and investigate the basic characteristics of pore-forming toxin ExlA.Methods The NY8755ΔexlA was constructed using the secondary homologous recombination method.C57BL/6J female mice ages 6 to 8 weeks were infected with NY8755 and NY8755 ΔexlA via aerosolized intratraheal inoculation respectively.Within 7 days of infection,the survival and weight changes of the mice were observed and recorded before the proinflammatory cytokines in the bronchoal-veolar lavage fluid(BALF)of the infected mice in the two groups were detected.Results The sequencing results showed that NY8755 ΔexlA was constructed.After 1×107 CFU NY8755 and NY8755 ΔexlA were infected,all the mice in the wild-type strain group died within 48 hours,while those in the mutant strain group began to die after 48 hours,and 40%of them remained alive 7 days later.The weight of surviving mice in the mutant strain group decreased but recovered gradually.After 12 hours of infection,there were more bloody exudates(redder in color)in the BALF of the wild-type strain group than in the mutant strain group,and the contents of proinflammatory cytokines interleukin-1β(IL-1β)and interleukin-17A (IL-17A)were significantly different. Conclusion Pseudomonas aeruginosa pore-forming toxin ExlA is the key pathogenic virulence factor of the exlA-positive Pseudomonas aeruginosa,which can significantly affect the survival status of mice and cause obvious inflammation in mice. Very little information is available on the action mechanisms of ExlA. In this study, The NY8755ΔexlA and the C57BL/6J mouse models infected with NY8755 and NY8755ΔexlA have been constructed that may be used for the investigation of pathogenesis of exlA-positive Pseudomonas aeruginosa.

Generation of MCM2 gene inducible knockout cervical cancer HeLa cells and its effect on DNA replication / 实用医学杂志

Objective To generate minichromosome maintenance protein 2(MCM2)gene knockout cervi-cal cancer HeLa cell lines using inducible CRISPR/Cas9 technology,and to explore the effect of MCM2 on DNA replication and replication stress.Methods The inducible CRISPR/Cas9 system,TLCV2,was used to construct MCM2 knockout HeLa cell lines.And the cell lines were divided into control group(Control),knockout group 1(KO1),and knockout group 2(KO2).Western blot,Edu incorporation experiment,real-time quantitative PCR(qPCR),immunofluorescence and MTT assay were used to analyze the effects of MCM2 knockout on DNA replica-tion and replication stress induced by hydroxyurea.Results The CRISPR/Cas9 system successfully knocked out the MCM2 gene after induction,and MCM2 knockout affected the stability of MCM2-7 complex.Compared with the control cells,MCM2 knockout cells had a dramatic decrease in the capacity of DNA replication,and the mRNA levels of Cyclin A1,Cyclin E1 and CDK4.Under DNA replication stress,MCM2 knockout cells decreased cell viability,DNA damage repair capacity,and increased genomic instability compared with control cells.Conclusion Knockout of MCM2 gene reduces the DNA replication capacity of HeLa cells under normal conditions and cell viability under replication stress.This study successfully generates MCM2 gene inducible knockout HeLa cell lines,laying the foundation for further research on the role and biological function of MCM2 gene in the occurrence and progression of cervical cancer.

Construction of hepatocyte-specific Sirt3 gene knockout mouse model / 安徽医科大学学报

Objective @#To construct hepatocyte-specific silence information regulator 3 ( Sirt3 ) gene knockout (Sirt3Δhep ) mice by Cre-loxP technique , and to provide an important animal model for further studying the biological function of the hepatocyte Sirt3 gene in diseases . @*Methods @#LoxP-labeled Sirt3flox/flox mice were mated with Alb-Cre homozygous (Alb-Cre + / + ) mice , and the F1 generation Sirt3flox/ - /Alb-Cre + / - mice were then mated with Sirt3flox/flox mice , and the F2 genotype of Sirt3flox/flox/Alb-Cre + / - mice were the Sirt3Δhep mice constructed in this ex- periment. Sirt3flox/flox/Alb-Cre - / - (Sirt3flox/flox ) mice were the control mice . Mouse tail genome DNA was extracted and PCR was used to identify the genotypes of the offspring mice . Immunofluorescence was used to detect Sirt3 ex- pression in mouse hepatocytes . Primary hepatocytes and tissue proteins of Sirt3Δhep mice were extracted , and the ex- pression of Sirt3 in mouse hepatocytes and other tissues was verified by Western blot. HE staining was used to ob- serve mice ′s liver , heart , spleen , and lung tissue structure . @*Results @#Sirt3Δhep mice were successfully identified .Immunofluorescence and Western blot results demonstrated a significant decrease in the expression of Sirt3 in the hepatocytes of these mice compared to the control group ( P < 0. 01) . At the same time , there was no significant difference in the expression of Sirt3 in the heart , spleen , kidney , and lung tissues of Sirt3Δhep mice compared with the control group (P > 0. 05) . The results of HE staining showed that the histological characteristics of the liver , heart , spleen , lungs , kidneys , and other major organs of Sirt3Δhep mice were not significantly different from those of the control group mice . @*Conclusion @#Hepatocyte-specific Sirt3 gene knockout mice are successfully constructed , which provides an animal model to explore further the role and molecular mechanism of the hepatocyte Sirt3 gene in diseases .

Construction and gene identification of myeloid specific Spi1 knockout mice / 安徽医科大学学报

Objective @#To construct myeloid specific Spi1 gene knockout mice and analyze their genotypes , so as to provide animal model basis for the study of pathological mechanism of diseases and drug targets .@*Methods @#According to the principle of CRISPR/Cas9 technology and C re/LoxP system , sgRNA and Donor vectors were de signed and constructed . The transcript of Exon 2 ( Exon 2) was used as the knockout region , and Loxp elements were placed on both sides of Exon 2 . Cas9 protein , sgRNA and Donor vector were mixed and microinj ected into the fertilized eggs of C57BL/6J mice , the fertilized eggs were transplanted into the uterus of C57BL/6J pregnant female mice , and F0 generation was obtained after 19 ~ 20 days . Positive F0 mice were mated with C57BL/6J mice to ob tain stable F1 Spi1 flox/ + mice . Spi1 flox/ + mice of F1 generation were selfed to obtain Spi1 flox/flox mice . Spi1 flox/flox mated with Lyz2-Cre + mice to obtain Spi1 flox/ + /Lyz2-Cre + mice , and then mated with Spi1 flox/flox , the Spi1 flox/flox/Lyz2-Cre + mice were myeloid specific Spi1 gene knockout ( KO) mice . Spi1 flox/flox/Lyz2-cre - mice were used as wild type (WT) mice . DNA of WT and KO mice was extracted , and the genotypes were identified by agarose gel electro phoresis after PCR amplification . Western blot was used to detect the expression of spleen focus forming virus proviral integration oncogene , Spi - 1 /purine rich box - 1(PU . 1) in immune cells of WT and KO mice .@*Results@#The results of PCR identification showed that the genotype of mice with only 220 bp amplified by flox primer was Spi1 flox/flox homozygote , and the genotype of mice with 700 bp amplified by Lyz2-Cre primer was Lyz2-Cre + . Western blot showed that compared with WT group , the protein PU . 1 was not expressed in bone marrow derived macropha ges (BMDMs ) and peritoneal macrophages (PM) in KO group (P < 0.01) . There was no significant difference of statistics in the expression level of PU . 1 in T cells between KO mice and WT mice . The results of PCR and West ern blot showed that myeloid specific Spi1 KO mice were successfully constructed . @*Conclusion @#The myeloid spe cific Spi1 gene KO mice are successfully constructed and identified , which provides animal model basis for further revealing the potential mechanism of PU . 1 inimmune regulation .

Analysis of peripheral immune cell typing in breast cancer lung metastasis model of miR-155 knockout mice / 中国免疫学杂志

Objective:To establish a mouse model of breast cancer lung metastasis with miR-155 knockout(miR155-/-)mice,and to compare the difference of peripheral blood immune cell typing between miR155-/-mice and C57BL/6J wide-type(WT)mice.Methods:Bioinformatics analysis was used to explore the expression level of miR-155 in breast cancer tissues and peripheral serum,and its relationship with prognosis.Mouse model of lung metastasis of breast cancer was established by tail vein injection;peripheral blood was collected for flow cytometry,and the immune cell typing was analyzed;the lung tissues were collected for immunohisto-chemical detection to observe the tumor metastasis.Results:Percentage of T lymphocytes and monocytes in peripheral blood of miR155-/-mice was significantly decreased compared with WT mice(P<0.05),percentage of myeloid inhibitory cells(MDSCs)was increased significantly(P<0.05),in which the proportion of monocyte subsets(M-MDSC)was significantly decreased(P<0.05),while the proportion of granulocyte subsets(G-MDSC)was significantly increased(P<0.05).In lung metastasis model of breast can-cer,percentage of T lymphocytes in peripheral blood of miR155-/-mice was significantly higher compared with WT mice,while per-centage of NK cells was decreased significantly(P<0.05),percentage of neutrophil was significantly decreased(P<0.001),propor-tion of Th cells in T lymphocytes was significantly decreased(P<0.05),proportion of M-MDSCs was significantly decreased(P<0.01),while proportion of G-MDSCs was significantly increased(P<0.01).Conclusion:Deletion of miR-155 gene leads to significant differences in peripheral immune cell typing,making mice more susceptible to lung metastasis of breast cancer.

Construction of HIF-1α gene knockout plasmid and functional verification in naked mole rats based on CRISPR/Cas9 system / 中国实验动物学报

Objective To construct plasmids and knock out HIF-1α gene expression in an naked mole rat skin fibroblasts(NSF)cell line using CRISPR/Cas9 genomic editing technology,to provide an in vitro cell model for studying the mechanism of hypoxia tolerance and the occurrence and development of hypoxia-related diseases in naked mole rats.Methods We designed four pairs of single guide RNA(sgRNA)sequences targeting exons 1～4 of the NSF HIF-1αgene and successfully constructed an expression plasmid.The plasmid with the optimal sgRNA was identified and transfected into 293T cells,and the supernatant was used for detecting the virus titer.Lentivirus particles carrying sgRNAs of HIF-1α were transfected into NSF cells which express Cas9 protein,based on a previous protocol.After transfection,fluorescence signals were observed under a fluorescence microscope,and HIF-1α expression in NSF cells was detected by Western Blot and T7 endonuclease 1(T7E1)analysis.Results Sanger sequencing showed that the designed sgRNA was successfully inserted into pX459 and pKLV2-U6-sgRNA2 vectors,demonstrating successful construction of a recombinant plasmid for transfection.T7E1 digestion successfully removed three bands and the target efficiency of sgRNA was 54％.Western Blot showed that the HIF-1α gene was successfully knocked out and its protein level was significantly reduced in NSF cells from naked mole rats(P=0.0019).There were no obvious morphological changes in HIF-1α-knockout cells under the microscope,and gene knockout had no obvious effect on cell proliferation.Conclusions We successfully constructed an HIF-1α-knockout cell line using CRISPR/Cas9 technology,to provide an experimental basis for further studies of the biological function of HIF-1α,as well as the mechanism of hypoxia tolerance in naked mole rats.The result also provide a theoretical foundation for the prevention and treatment of hypoxia-related diseases.

Identification of a new C-23 metabolite in sterol degradation of Mycobacterium neoaurum HGMS2 and analysis of its metabolic pathways / 生物工程学报

Mycobacterium neoaurum has the ability to produce steroidal intermediates known as 22-hydroxy-23, 24-bisnorchol-4-en-3-one (BA) upon the knockout of the genes for either the hydroxyacyl-CoA dehydrogenase (Hsd4A) or acyl-CoA thiolase (FadA5). In a previous study, we discovered a novel metabolite in the fermentation products when the fadA5 gene was deleted. This research aims to elucidate the metabolic pathway of this metabolite through structural identification, homologous sequence analysis of the fadA5 gene, phylogenetic tree analysis of M. neoaurum HGMS2, and gene knockout. Our findings revealed that the metabolite is a C23 metabolic intermediate, named 24-norchol-4-ene-3, 22-dione (designated as 3-OPD). It is formed when a thioesterase (TE) catalyzes the formation of a β-ketonic acid by removing CoA from the side chain of 3, 22-dioxo-25, 26-bisnorchol-4-ene-24-oyl CoA (22-O-BNC-CoA), followed by spontaneously undergoing decarboxylation. These results have the potential to contribute to the development of novel steroid intermediates.

Effect of intestinal Metrnl gene knockout on intestinal microbiota and ulcerative colitis / 药学实践与服务

Objective To investigate the effect of intestinal Metrnl on dextran sodium sulfate (DSS)-induced ulcerative colitis mouse model and the regulation mechanism of intestinal microbiota. Methods Different concentrations of DSS (3% DSS and 1% DSS) were used to induce ulcerative colitis on C57 mice to determine the experimental conditions. Intestinal epithelial Metrnl specific knockout mice (Metrnl(-/-)) and its control mice (Metrnl(+/+)) were administrated with 3% DSS for 5 d. Then the survival time, body weight, DAI (disease activity index), colon length and pathological changes in colon tissues were observed. 16S ribosomal RNA gene sequencing was used to detect the composition of intestinal microbiota. Results Compared with 1% DSS, 3% DSS could significantly aggravate ulcerative colitis on C57 mice, such as lower survival rate (P<0.05), more weight loss (P<0.05), higher DAI score (P<0.05), shorter colon length (P<0.05) and higher pathology score (P<0.05). After administrated to 3% DSS for 5 d, comparing with Metrnl(+/+) mice, Metrnl(-/-) mice showed more weight loss (P<0.05), higher DAI score (P<0.05), shorter colon length (P<0.05) and higher pathology score (P<0.05). The 16S ribosomal RNA results showed that the diversity of intestinal microbiota in Metrnl(-/-) mice significantly decreased. Furthermore, Bacteroidetes and Proteobacteria significantly decreased, while Firmicutes increased. Conclusion Metrnl could protect the DSS-induced ulcerative colitis mouse through regulating intestinal microbiota.

Murine models of cerebral cavernous malformations / 国际脑血管病杂志

Cerebral cavernous malformations (CCMs) are the common cerebrovascular malformation. Its incidence was 0.16%-0.5%. CCM can exist in both sporadic and familial forms, with the latter being inherited in an autosomal dominant manner. Its pathogenesis is associated with mutations in the CCM1, CCM2, and CCM3 genes. The somatic mutations of these genes are the basis for the occurrence of brain lesions. In order to explore the pathogenesis of CCM and identify therapeutic targets, various CCM animal models have been developed, providing assistance for the study of the pathological and physiological mechanisms of CCM. However, each CCM model has its own advantages, disadvantages, and applicability. Mice are the most commonly used animals to model CCM. Therefore, this article summarizes the characteristics and research progress of current murine CCM models.

Macrophage MED1 deficiency promotes the development of atherosclerosis in female ApoE and LDLR knockout mice / 西安交通大学学报(医学版)

【Objective】 To study the effect of macrophage mediator 1 (MED1) deficiency on atherosclerosis in female mice. 【Methods】 ApoE knockout (ApoE-/-), LDLR knockout (LDLR-/-), MED1fl/fl, and macrophage MED1 knockout (MED1△Mac) mice were recruited in the study. Two types of mouse model were constructed:ApoE and macrophage MED1 double knockout (MED1△Mac/ApoE-/-) mice and their littermate controls (MED1fl/fl/ApoE-/-). ② LDLR knockout (LDLR-/-) mice receiving bone marrow from MED1△Mac (MED1△Mac→LDLR-/-) or MED1fl/fl (MED1fl/fl→LDLR-/-) mice. Female mice from these two models were fed a Western diet (21% fat and 0.15% cholesterol) for 12 weeks to promote the development of atherosclerosis. Body weight, total cholesterol (TC), and total triglyceride (TG) content in plasma were measured dynamically. After Western diet feeding for 12 weeks, aortic tree and aortic root were collected and hematoxylin-eosin (H&E) and oil red O staining were performed. 【Results】 Plasma TC and TG did not significantly differ between MED1fl/fl/ApoE-/- control group and MED1△Mac/ApoE-/-experimental group. However, the plaque area in aortic tree and aortic root was significantly increased in MED1△Mac/ApoE-/-mice. Moreover, compared with that in MED1fl/fl→LDLR-/- control group, the plaque area of aortic tree and aortic root had an increasing trend in MED1△Mac→LDLR-/- mice group. 【Conclusion】 MED1 deficiency in macrophages promotes the development of atherosclerosis in female ApoE or LDLR knockout mice.

Progress in depression research using genetically modified animal models / 中国实验动物学报

Depression is a complex mental disease with polygenic inheritance and a high incidence.Our understanding of the clinical manifestations and pathogenesis of depression has recently improved.Continuous progress in gene-editing technologies has increased the construction efficiency and reduced the cost of gene-knockout animals,leading to their increasing use in the fields of basic research and drug development for depression and providing a powerful tool for revealing the pathogenesis of depression.In this review,we summarize recent progress in understanding the roles and mechanisms of candidate genes in depression using knockout model mice.

Construction of macrophage-specific MST1 knockout mouse model / 安徽医科大学学报

Objective @# To establish myeloid ( including macrophage and granulocyte) specific knockout mice of mammalian sterile line 20-like kinase 1 (MST1) gene for furtherinvestigating the role and the mechanism of MST1 in macrophages in related clinical diseases．@*Methods @#Mst1flox/flox LysM-Cre ( referred to as Mst1ΔM/ΔM hereafter) mice were generated by crossing Mst1flox/floxwith lysozyme (Lysm-Cre) mice．The loxP site and Cre gene were amplified by PCR for genotyping．The knockdown efficiency of MST1 in macrophages was verified by quantitative PCR and immunofluorescence．The main immune cell populations in the livers were detected by flow cytometry. @*Results@#Mst1flox/flox LysM-Cre (Mst1ΔM/ΔM ) was the genotype of macrophage specific knockout MST1 mice．The results of qPCR and immunofluorescence showed that the knock-out efficiency of MST1 was more than 70% in bone marrow- derived macrophages and peritoneal macrophages．Flow cytometry showed that macrophage knockout of MST1 had no significant effect on the main immune cell populations in the liver of mice．@*Conclusion @# Macrophage-specific knockout of MST1 mouse model is successfully established，which lays a foundation for further investigation on the role and mechanism of macrophage MST1 in clinical related disease.

Construction of phosphodiesterase 4D homozygous knockout mice / 安徽医科大学学报

Objective @#The CRISPR / Cas9 technology was applied to construct PDE4D homozygous knockout mice to provide a basis for in-depth investigation of PDE4D gene function and mechanism of action．@*Methods@#A vector was constructed for PDE4D gene exon 4，5 microinjected into fertilized eggs of C57BL /6J mice，and PDE4D －/ - mice were obtained after maternal breeding and offspring mating，and the mice genotypes were determined by PCR product sequencing and genotype identification techniques．Changes in morphology and function of the major organs of the mice were detected using an ultrasound imaging system and H＆E staining，and the expression of PDE4D protein in the mice was verified by Western blot assay. @*Results @#The PDE4D －/ － mouse genotype was stably inherited， the mice were small，and there were no obvious morphological and histological changes in the major organs in vivo. The PDE4D expression was reduced or largely absent in the major tissues of PDE4D heterozygous or pure knockout mice，and the knockout effect was better．@*Conclusion @#PDE4D －/ － mice were successfully established using CRISPR / Cas9 technology，and no significant physiological abnormalities were found，which could be used for disease pathogenesis and drug research using PDE4D as the target.

Effect of ACE2 deletion on vasoconstriction reactivity of aortic segments in mice with tourniquet shock / 中国病理生理杂志

AIM:To observe the effect of angiotensin-converting enzyme 2(ACE2)deletion on vasoconstric-tion reactivity of aortic segments in ACE2 knockout(KO)mice with tourniquet shock(TS).METHODS:The 8-month-old male mice with C57BL/6 background were divided into wild-type(WT)control group,WT-TS group,KO group and KO-TS group,with 10 mice in each group,of which five were used for determination of vascular reactivity,and the other five for the other assays.The hindlimbs of the mice in WT-TS group and KO-TS group were ligated with tourniquet for 2 h and loosened for 4 h.The mice in WT group and KO group were subjected to the same treatment except for tourniquet liga-tion.The vasoconstriction reactivity of the aorta was measured on tensiometer.The morphological damage of the aorta was evaluated by vascular histopathology.Western blot was used to detect the expression of AT1,MAS,ACE and ACE2 pro-teins in aorta.The serum levels of angiotensin(Ang)Ⅱ and Ang-(1-7)were determined by enzyme-linked immunosorbent assay.RESULTS:Compared with WT group,the mice in WT-TS group had lower vascular reactivity to norepinephrine(NE)and obvious vascular lesions.The expression of ACE protein increased significantly(P＜0.01),while the expres-sion of ACE2 decreased(P＜0.05).The expression of AT1 protein in aorta decreased significantly,the expression of MAS protein increased significantly,and the AT1/MAS ratio decreased(P＜0.01).Serum Ang II level increased,serum Ang-(1-7)level decreased,and Ang Ⅱ/Ang-(1-7)ratio increased(P＜0.05).Compared with WT group,vascular reactivity in KO group increased at low concentration of NE(＜10-7 mol/L),and decreased at high concentration(＞10-7 mol/L)without vascular lesion.The expression levels of aortic AT1,MAS and ACE were all elevated(P＜0.05).The serum level of Ang Ⅱ increased(P＜0.05),but the level of Ang-(1-7)had no obvious change.Compared with KO and WT-TS groups,the aortic reactivity in KO-TS group subtracted apparently(P＜0.05),representing its curve shifting to the right obviously.The morphological damage aggravated slightly,and the expression of AT1 and ACE increased slightly in KO-TS group com-pared with WT-TS group(P＜0.05).However,the expression of MAS increased significantly in vascular tissue(P＜0.01).The serum levels of Ang Ⅱ and Ang-(1-7)further increased and decreased,respectively,and the Ang Ⅱ/Ang-(1-7)ratio increased(P＜0.01).CONCLUSION:Deficiency of ACE2 induces severe aortic hyporeactivity to NE during TS,which may be related to the increased imbalance of renin-angiotensin system in ACE2 gene knockout mice.

Generation of Mlk3 KO mice by CRISPR/Cas9 and its effect on blood pressure / 生物工程学报

To explore the effect of Mlk3 (mixed lineage kinase 3) deficiency on blood pressure, Mlk3 gene knockout (Mlk3KO) mice were generated. Activities of sgRNAs targeted Mlk3 gene were evaluated by T7 endonuclease I (T7E1) assay. CRISPR/Cas9 mRNA and sgRNA were obtained by in vitro transcription, microinjected into zygote, followed by transferring into a foster mother. Genotyping and DNA sequencing confirmed the deletion of Mlk3 gene. Real- time PCR (RT-PCR), Western blotting or immunofluorescence analysis showed that Mlk3KO mice had an undetectable expression of Mlk3 mRNA or Mlk3 protein. Mlk3KO mice exhibited an elevated systolic blood pressure compared with wild-type mice as measured by tail-cuff system. Immunohistochemistry and Western blotting analysis showed that the phosphorylation of MLC (myosin light chain) was significantly increased in aorta isolated from Mlk3KO mice. Together, Mlk3KO mice was successfully generated by CRISPR/Cas9 system. MLK3 functions in maintaining blood pressure homeostasis by regulating MLC phosphorylation. This study provides an animal model for exploring the mechanism by which Mlk3 protects against the development of hypertension and hypertensive cardiovascular remodeling.

Effects of Bcl3 gene knockout on composition of spleen immune cells and antitumor ability of mice / 中华微生物学和免疫学杂志

Objective:To investigate the effects of Bcl3 gene knockout on the composition of spleen immune cells and antitumor ability of mice.Methods:Bcl3 gene knockout mice (Bcl3 -/-) were established by CRISPR/Cas9 genome editing technology. Blood routine test and flow cytometry were used to detect the immune cell composition in Bcl3 -/- mice. Lung metastasis models were established by injecting mice with B16F10 melanoma cells. The number of tumor nodules in lung and the survival time of mice were used to assess the antitumor ability of wild-type (WT) and Bcl3 -/- mice. Results:Bcl3 -/- mice were successfully bred to a strain with normal growth rate and normal breeding performance. Furthermore, no embryonic death occurred. Compared with WT mice, Bcl3 -/- mice showed splenomegaly and a significant increase in the number of spleen immune cells ( P<0.05). The counts and percentages of platelets and neutrophils in Bcl3 -/- mice were significantly lower than those in WT mice. The proportion of CD19 + B cells showed no significant change, while the proportions of CD3 + T cells and T cell subsets (CD4 + , CD8 + , Treg) increased significantly ( P<0.05). The proportions of NK cells (NK1.1 + ) and neutrophils (Gr1 + ) decreased ( P<0.05), while no significant change in the proportion of DC (CD11b + ) was observed. There were a large number of tumor nodules formed by melanoma cells in the lung of Bcl3 -/- tumor bearing mice, and their survival time was shortened dramatically. Conclusions:Knockout of Bcl3 gene affected the development, differentiation and function of immune cells, thereby reducing the antitumor ability of mice.

Effect of Ethyl Acetate Extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis on Intestinal Flora in ApoE-/- Mice with Atherosclerosis / 中国实验方剂学杂志

ObjectiveTo observe the effect of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis on high-fat diet-induced apolipoprotein E gene knockout （ApoE-/-） mice， and explore its mechanism of treating atherosclerosis by regulating intestinal flora. MethodThirty-two 8-week-old male ApoE-/- mice were randomly divided into model group， rosuvastatin group （10 mg·kg-1）， high-， low-dose groups of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis （75， 25 mg·kg-1）， with 8 mice in each group. Eight C57BL/6 mice were used as blank group. After 8 weeks of continuous administration， blood was taken to determine the blood lipid level. Enzyme-linked immunosorbent assay （ELISA） was used to detect the contents of related indexes in serum of mice. Hematoxylin-eosin （HE） staining was used to observe the formation of aortic plaque in mice. Cecal contents were collected and 16S rRNA amplicon sequencing was used to detect intestinal flora. ResultCompared with the blank group， the plaque area of the model group was significantly increased with inflammatory infiltration， the contents of triglyceride （TG）， total cholesterol （TC）， low-density lipoprotein cholesterol （LDL-C）， inflammatory factors and inducible nitric oxide synthase （iNOS） were increased， while the content of high-density lipoprotein cholesterol （HDL-C） was decreased. Compared with the model group， rosuvastatin group and high- and low-dose groups of ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis could improve the deposition of aortic plaque， reduce the contents of TG， TC， LDL-C， inflammatory factors and iNOS， and increase the content of HDL-C. Compared with the blank group， the relative abundances of Firmicutes and Proteobacteria in the model group increased， while the relative abundance of Bacteroidetes decreased. Alpha and Beta diversity analysis showed that samples of each group could be significantly isolated， and the total number and abundance of intestinal flora species in the model group were low. Compared with the model group， ethyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis could increase the relative abundance of beneficial bacteria and decrease the relative abundance of pathogenic bacteria. ConclusionEthyl acetate extract of Acanthopanacis Senticosi Radix et Rhizoma seu Caulis was mainly composed of flavonoids， which can treat atherosclerosis by regulating the intestinal flora and improve the pathological changes in the aorta of ApoE-/- mice induced by high-fat diet. The mechanism may be related to its ability to reduce the level of inflammatory factors， improve antioxidant capacity and repair the disorder of intestinal flora structure.